Pretreatment of glucose feedstock

Abstract

Commercial glucose solutions used as feedstock for enzymatic conversion of glucose to fructose by glucose isomerase often contain materials which act as poisons toward the enzyme. It has been found that these poisons can be removed, or destroyed, by treatment of the feedstock with oxidizing agents, chief of which is hydrogen peroxide.

What is claimed is: 
     
       1. In a method of converting glucose to fructose using an immobilized glucose isomerase system, the improvement wherein a feedstock containing glucose and minor amounts of isomerase poisons, prior to contacting with the immobilized glucose isomerase system, is treated with an oxidizing agent selected from the group consisting of peroxides, hypohalites, perhalates, and persulfates at a pH from about 6 to about 9 at a temperature from about 10° to about 80° C. for a time and in an amount effective to increase the productivity of said immobilized glucose isomerase system above that productivity occurring when the enzymatic isomerization is carried out without the presence of said oxidizing agent, the treatment being for a time sufficient to destroy said poisons. 
     
     
       2. The process of claim 1 where the oxidizing agent is hydrogen peroxide. 
     
     
       3. The process of claim 1 where the oxidizing agent is a hypochlorite. 
     
     
       4. The process of claim 1 where the oxidizing agent is a perchlorate. 
     
     
       5. The process of claim 1 where the pH is between about 7.5 and about 9. 
     
     
       6. The process of claim 1 where the temperature is from about 50° to about 70° C. 
     
     
       7. The process of claim 1 further characterized in that residual oxidizing agent is removed prior to said enzymatic conversion. 
     
     
       8. The process of claim 1 where the effective amount is from about 50 to about 500 ppm. 
     
     
       9. The process of claim 1 where the amount is from about 50 to about 250 ppm.